Practice keyboard



Nov. 12, 1929, G. JONES PRACTICE KEYBOARD Filed May 17 1926 INVENTOR GAlFF/f/f fo/vss,

BY ATTORNEYS.

Patented Nov. 12, 1929 UNITED STATES PATENT OFFICE GRIFFITH JONES, OF ANDERSON, INDIANA, ASSIGNOR OF ONE-HALF TO H. G. NEELY AND ONE-HALF TO W. H. FORSE, JR., OF ANDERSON, INDIANA PRACTICE KEYBOARD Application filed May 17,

This invention relates to a keyboard mechanism. The chief object of this invention is to provide a keyboard mechanism which simulates piano or organ key action without producing sound and which is portable, adjustable and of but few parts.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

In the drawings Fig. 1 is a perspective View of a keyboard mechanism showing the same in exposed relation for operation. Fig. 2 is an enlarged transverse sectional View showing the device in closed position, the dotted lines indicating the device in the uncovered position for operation. Fig. 3 is an elevational View with parts broken away showing the parts in section of a portion of the end wall and combination stop and tension supporting means. Fig. 4 is a modification thereof. Fig. 5 is a still further modified form of the same.

Fig. 6 is a transverse section taken on line 66 of Fig. 2 and in the direction of the arrows, the dotted lines indicating the pin and key in engagement.

In the drawings 10 indicates a base secured to which is the front closure portion 11 and in spaced relation the back 12. The front portion does not extend to the same height as the back and the difference is provided by a movable front 13 carried by the movable top portion 14 hingedly supported at 15 to another top portion 16 secured in rigid relation. The two end walls 17 complete the compartment and access is had to the key mechanism therein when the lid is tilted from the full line position shown in Fig. 2 to the dotted line thereof. The lid is secured in closed position by suitable means and said lid also supports the handle 18 whereby the entire device may be readily carried about.

Positioned in substantially parallel relation and within the casing described are a plurality of white keys l9 and shorter black keys 20 substantially similar to those of a piano or organ action. A cushion strip 21 is positioned adjacent the front end of the casing on the bottom 10 and adjacent thereto is another 1926. Serial No. 109,519.

strip 22, said strips being engageable upon depression by the keys 19 and 20 respectively.

Each of the keys is provided with a longitudinally extending milled slot 23 receiving a guide pin 24 extending upwardly from the bottom and preferably in the form of a nail driven through the bottom or anchored thereto. The rear end of the key is fulcrumed or bears on a fulcrum rod 25 and adjacent thereto is a pin 26 secured to the base and which is receivable by an opening 27 in the key. The fulcrum rod 25 thus secures full width key bearing and a suitable cushion 28 positioned above said key through the medium of a strip 29 adjustably mounted by means 30 determines the initial level or position of the keys. Suitable means 31 also assists in anchoring the fulcrum rod 25.

A cushioned cross member or stop rail 32 is suitably supported in spaced relation above the bottom and therebetween is positioned the several keys, said keys normally bearing on the bottom thereof, the cushion material being felt secured thereto. The cross member 32 supports a plurality of staples 34 and each of the keys supports a staple 35 and upon the same are mounted the coil springs 36.

It will be apparent that in the aforesaid construction, movement of the cross member 32 towards and away from the bottom 10 will adjust the position of the keys as desired. Fig. 2 shows the cross member secured in fixed position and as illustrated in Figs. 3 and 4 the end member 17 is notched or recessed at 40 to receive the ends which are se cured by screw bolts 39 or adjusted by the set screws 41 or 42, see Figs. 3 and 4, through the bottom 10, while screw 42 extends through the cross member 32 and bears upon the seat formed by the recess in the end member 17.

A spring tension adjusting device is shown in Fig. 5, wherein a spring supporting rod 132 is provided. This may be cylindrical or may have trunnion ends cylindrical in form. The springs 136 each are secured as at 135 at one end to a key and at the opposite end .at 134 to said rod. Screw clamp 139 may be backed out, which releases clamp 117 from rod 132 which thereupon may be turned in its bearings and then re-clamped in the adjusted posit-ion. The tilting of the circular portion of said rod will either lengthen or shorten all of the normal spring length and thus the tension of the springs will be changed although the bearing of the keys 19 and 20 on the transverse felt or cushion 33 will not be changed thereby and said adjustment is maintained by the clamping portion 117 and clamping screw 139.

The invention claimed is:

1. A keyboard mechanism comprising a supporting member having a curved fulcruming and combination key supporting and fulcrumed surface, a plurality of parallel key members positioned thereabove and bearing substantially full key width on said curved surface and adjacent one end of said key members, means positioned above said key members adjacent the supporting member for adjusting the elevation of the key members substantially as described.

2. A device of the character defined by claim 1, characterized by the addition of a cross member positioned above said key members and extending transversely thereof, and yielding means for normally maintaining said key members in engagement with said cross member and limiting the upper position of the same.

3. A device of the character defined by claim 1, characterized by the addition of a cross member positioned above said key members and extending transversely thereof, yielding means for normally maintaining said key members in engagement with said cross member and limiting the upper position of the same, and means adjustably mounting said cross member for varying the normal position of the keys.

4:. In a keyboard mechanism, the combination of a key member containing a longitudinally milled slot, a pin receivable thereby and preventing lateral movement of said member, another pin associated with said key member for guiding the same, a fulcrum member supporting the key member adjacent the last mentioned pin and retained thereby, a cross member extending transversely of the key member and intermediate the pins, and yielding means connecting said key member to said cross member for normally maintaining said key member in engagement with the cross member.

5. A keyboard mechanism including a plurality of key members, each of the character defined by claim 4 and mounted according to claim 1, said fulcrum member and said cross member being common to all key members, means adjustably mounting the cross member, and yielding means connecting said key members to the cross member.

In witness whereof, I have hereunto affixed my signature.

GRIFFITH JONES. 

